Cooperative Effects of Aniline with DMSO in Ru-II Complexes: Tuning the Reactivity for Ring-Opening Metathesis Polymerization

Author(s)

Martins, Daniele M. ^[1] ; Maia, Pedro I. S. ^[2] ; Carvalho-Jr, Valdemiro P. ; Lima-Neto, Benedito S. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Fed Triangulo Mineiro, Dept Quim, BR-38025440 Uberaba, MG - Brazil

• Document type: Journal article
• Source: European Journal of Inorganic Chemistry; v. 2019, n. 41, p. 4421-4426, NOV 10 2019.
• Web of Science Citations: 2

Abstract

The complex cis,fac-{[}RuCl2(DMSO-O)(DMSO-S)(3)] {[}1] reacted with aniline (NH2Ph) under reflux to produce the complex trans,cis,cis-{[}RuCl2(DMSO-S)(2)(NH2Ph)(2)] {[}2], whereas at room temperature the resulting complex was cis,fac-{[}RuCl2(DMSO-S)(3)(NH2Ph)] {[}3]. The complexes were characterized by FTIR, EPR, H-1 and C-13 NMR, electronic spectra, and the crystal structure of 2 was determined by single X-ray crystallography. The influence of NH2Ph and DMSO as ancillary ligands in the new complexes was then evaluated for ring-opening metathesis polymerization (ROMP) of norbornene (NBE), norbornadiene (NBD), and dicyclopentadiene (DCPD) in presence of ethyl diazoacetate (EDA) with different {[}monomer]/{[}Ru] molar ratios. Homopolymers of NBE with molecular weights in the order of magnitude of 10(5) g.mol(-1) and insoluble polymers in CHCl3 from NBD and DCPD were obtained in different yields depending of the starting complex, reaction time (5 and 30 min), and temperature (25 and 50 degrees C). Valorous results were obtained for polyNBD, polyDCPD, and copolymerizations from NBE with NBD or DCPD using the new complexes, affording higher yields than with 1. In conclusion, beneficial effects are observed when DMSO and the weak sigma-donor NH2Ph ligands are arranged in the same coordination sphere of Ru(II) pre-catalysts for ROMP. (AU)

• FAPESP's process: 18/06340-1 - Bimetallic complexes of ruthenium(II) and nickel(II): coupling of mechanistically-incompatible reactions using multifunctional catalysts via tandem catalysis
• Grantee: Valdemiro Pereira de Carvalho Júnior
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/06329-5 - Development of ruthenium complexes with ammines as ancillary ligands for homogeneous catalysis of ring opening metathesis polymerization of cyclic olefins
• Grantee: Benedito dos Santos Lima Neto
• Support Opportunities: Regular Research Grants